Studies will be carried out on three individual projects: 1). The electrophysiological properties of ACTH-secreting tumor cells will be studied in more detail and such studies extended to primary pituitary cultures. 2). Spectral characteristics of inhibitory noise will be examined at synapses in the brainstem of the Lamprey. Noise produced by various putative transmitters will be compared with that produced by activation of inhibitory pathways. 3). Further ultrastructural studies will be done on synapses in the ciliary ganglion of the chick, with particular reference to structural changes occurring after axotomy.